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Thread: Stan_Ham diode driver (analog)

  1. #131
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    Is it possible to run multiple PHR803 diodes from one stan ham driver? And what would be the preferred way to do this (series, parallel)?
    Life is short.... Ride it hard!!

  2. #132
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    Frixxion:
    I will not advice you to do that. Every laser diode during operation requires it's own current value. So if you run multiple diodes from one driver then one diode will be overpowered while others underpowered.

  3. #133
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    , because he might have had people looking at the wrong place when what we should be examining is a diode we were told was not at all important for forward bias protection for the laser diode. If this is an illusion feel free to dispel it. But as clearly as possible, because I'm lousy at riddles.[/QUOTE]
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    Its not a mcguffin, I'm privy to what was inside when somebody else smashed one, but there will be no shouting "Hey Bill, your patenting prior art". It truely is a unique combination I've never seen before and would not have thought of.

    Ever think that his discussions with us were to see if he missed something?
    Ever think it was the frustrated teacher that exists in all engineers, trying to get us to learn and experiment? I don't see any misleading tactics. Bravo for him for even broaching the subject. He could have just said, buy this, it works, and we don't talk about alternatives. Instead, he made videos, showed the failures of other products and admitted that some folks came close, but no cigar, ie the AT&T product.

    If your so sure he's pulling a fast one, buy one and smash it. You might be shocked at whats inside. Its NOt anything that any of us suggested.

    I'm gonna possibly need quite a few for a project I'm doing for someone who needs a emp proof product, so I'm not gonna enrage Pangolin, Inc, by reverse engineering it. I have no need to nor the time, and I would be fired in a heartbeat if I knowingly copied someone's IP. I work for a company that worships proper patents and depends on the system to protect its own unique works.

    And I assure you, the person who smashed it, and scanned it via a uncanny mental telepathy would have posted in half a nanosecond if it was a ripoff. It is not.

    Bill is right to not disclose his work, until he is protected by the patent. And I don't think you'll see it under Pangolin Inc, that would make it too easy to clone.

    For once, somebody came up with a actual new way of doing things, a rare event.

    It works, and if you want to save a 125$ investment in a 635 nm diode, as I do, buy it. If NOT, come up with something better.

    But lets not shoot down a enterprising business man for doing what is in his companies best interest. I mean he makes it freely available and probably not a huge profit. He could have just licensed it and ignored us, but it is available in Q1 to individuals, and that is a rare thing considering how the market is.

    I have a hard timing doing product development in America, its hard to get parts for production of exotic stuff here, so I admire the fact that it is available. I need 60% american made gear for my project, and that is proving nearly impossible.

    Steve
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    When I still could have...

  4. #134
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    Hmm, that's not quite the answer I was hoping for.. What if I don't really care about my diode's life? Would it be possible then?
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  5. #135
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    Quote Originally Posted by Frixxion View Post
    Hmm, that's not quite the answer I was hoping for.. What if I don't really care about my diode's life? Would it be possible then?

    If you put them in series and run them within the data sheet limits, no problem for n = 2. You may not get peak brightness out of both devices as rarely do their current vs output responses match. This assumes your driver has enough headroom for two voltage drops, ie if each diode needs 2.4V to turn on and you only have a 5.0V supply, you'd only have .2V of headroom , not enough for most drivers to even work. Assume a pass transistor in the driver needs .7 to 1.2V to work itself, so on a 5V driver, 2.4 + 2.4 + 1.2 = more voltage needed then the 5V supply can source, yet a 12V supply could easily do 3 diodes at that point.... Get the idea?

    More then 2 in series your asking for trouble in most cases

    running them in parallel without some means to force current sharing will be a disaster.

    remember you need to float the diode housings from case ground and each other if you do this....

    Steve
    Qui habet Christos, habet Vitam!
    I should have rented the space under my name for advertising.
    When I still could have...

  6. #136
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    Blueray diodes need around 5V to operate, so its not possible with bluray unless your driver can handle 12V input.

    There are big OEM laser companies who are driving diodes in series.

  7. #137
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    Hehe.

    It's clear that The Doctor's got a thing for me... He'd love to take me down a notch by trying to catch me in a lie, or by trying to convince people that I've been misleading them, etc. But the fact of the matter is, I'm not... Everything that I have written in the past is absolutely true. Everything on the LASORB web site is absolutely true. If it wasn't, I would have no credibility. You can fool some of the people some of the time, but eventually you'd get caught... So I don't play that way.

    One reason the silence has been deafening (if Doc means I haven't corrected him on his posts and theories) is because I've been quite busy, and also because Doc's rant is in a forum topic I don't look at very often anyway...

    Steve has been critical of me in the past. We can't say he's exactly a Pangolin plant. Steve speaks his mind. So if Steve says this thing is real, it's not because he's naturally pro-Pangolin. It's because he believes it.

    As for patents, novelty, etc. the fact that folks are buying this -- not only hobbyists on PL wanting to protect their laser pointers, but some of the top companies in the entire world -- who have tested it and believe it works -- tells you that this thing is not obvious and that it works.

    Thanks for the kind words Steve. Sure, people can "smash one" and see what's inside. But... hehe... the real magic isn't the "what", but actually some of the details.

    For example, if we believe everything we read, the company Cinabon gets their cinnamon for their buns in some far-off place (I forget whether it's Egypt or Africa) and they say that's the only place that has this perfect kind of cinnamon. And anyone who has ever eaten a Cinabon can tell you that it is like no other cinnamon bun on earth.

    In order to work from DC to 1GHz, LASORB needs components that are very unique. One of the reasons why it took us a year to perfect is because it took nearly that long to find the special components, and so far -- like Cinabon, we've only been able to find those components one place on earth. So -- even if people knew what was in there, they wouldn't really be able to make one. Sort of like nobody can take any old cinnamon and make a bun that is as good as Cinabon...

    As for refuting what Doc wrote, or what others believe, actually I'm having a lot of fun watching people try to guess what's inside that little capsule.

    Best regards,

    William Benner

  8. #138
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    Hey Anthony!

    Im planning to use the unamped output signals from a Soundcard DAC directly to modulate my Lasers. Can your design be changed so i get the max set current at a desired (currentyl unknown) input voltage? without blasting the diode by going above that...

  9. #139
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    With regards to soft-starting the diode circuit, wouldn't the easiest option be to make either a delayed start circuit with a 555, or a start circuit that only powers up the diode power lines if the PSU voltages reach a certain threshold (using fx. a few comparators)? Professional audio amps use the same trick for years.

    I wouldn't use a relay to switch the diode, since that would introduce more spikes, but a MOSFET pulling the modulation line to ground should be an OK option.

  10. #140
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    How about just slugging the base/emitter junction with some capacitance? On start up it will take a while to come up to ~0.7V, where it will (approximately) then sit.

    Now, I dislike the opamp in the feedback loop (seen them do too many funky things), so how about going old school and just using an emitter resistor to set the current, with a thermally tracking diode junction to trim out the Vbe?

    The voltage at the opamp output sets the current as (Vb - Vbe)/Re in the normal way, and T2 which should thermally track T1 produces a constant Vbe which is added to the control voltage applied to the opamp.

    You need an opamp that has an input range down to below 0.7V of the negative supply and an output that can also get right down there (or the thing will not turn off!).

    Ignore the component numbers, it is a sketch done in the corner of something more complex...

    As to laser diode protection I am thinking about dv/dt limits and triacs (add a series cap in parallel with a high value resistor so that when the event has passed the cap can discharge with a current below the device holding current....

    Obviously the cap needs to be large enough to hold the charge from the esd event while remaining below laser voltage, and the discharge resistor must be high enough to prevent the thing latching on (and you would use a triac type structure in reality), but I don't see why not...

    The old school Unijunctions (Can you still get those things?) may have some applicibility here.

    Regards, Dan.
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